Air heater



May 29,1928. 1,671,189

H. F. GAUSS AIR HEATER Filed Jan- 14, 1926 y 62 1.2 X 110W!!! A TTORNE )0.

Patented May 29, 1928.

UNITED STATES PATENT OFFICE.

HENRY I. GAUSS, OF MOSCOW, IDAHO, ASSIGNOR TO HEINE BOILER COMPANY, OF ST. LOUIS, MISSOURI, A CORPORATION OF MISSOURI.

AIR HEATER.

Application filed January 14, 1926. Serial No. 81,334.

This invention relates to heating devices of the kind that are used for causing one gaseous medium to be heated by another gaseous medium of a higher temperature, and particularly, recuperat-ive air heaters of the tubular type that are used with boilers for heating air that is supplied to the furnace of the boiler to support combustion.

One objection to air heaters of the type mentioned is that the gases, in flowing through the heater, tend to form lanes at the centers of the tubes which constitute the gas passageway, thereby resulting in low efficiency, due, of course, to the fact that the 5 gases do not remain in contact with the elements that are used to absorb the heat from the gases and transmit said heat to the air that flows through the heater.

The main object of my invention is to provide a recuperative heater of the tubular type that is equipped with one or more mixing chambers for breaking up the lanes formed in the gas passageway, thereby insuring the gases circulating through the 95 heater in direct contact with the air heating elements, and consequently, increasing the efliciency of the heater. 7

Another object is to provide an inexpensive and efficient air heater which is of such construction that soot, dust and the like can be removed easily from the gas passageways.-

Figure l of the drawings is a side elevational view, illustrating an air heater constructed in accordance with my invention combined with a boiler for heating the air that is supplied to the furnace of the boiler to support combustion. I

Figure 2 is a vertical longitudinal sectional view of said heater; and

Figure 3 is a horizontal sectional View, taken on the line 3-3 of Figure 2.

Referring to the drawings which illustrate the preferred form of my invention, A designates a boiler or other heating apparatus provided with a gas outlet through which the gases or products of combustion escape, as indicated by the arrows at in Fig ure 1, B designates my improved air heater which is arran ed the path of said escaping gases, designates a fan or other suitable suction device for drawing the gases through the heater. B and D designates a fan or blower for drawing air through said heater and thereafter forcing said air under the grate or into the combustion. chamber of the furnace of the boiler, as indicated by the arrows y in Figure 1.

The air heater B is provided with tubular elements arranged to form a substantially straight passageway through which the escaping gases travel without reversals, a means for causing air to circulate over the exterior of said elements and absorb heat from same, and a means for overcoming the tendency of the gases to form lanes in circulating through the heater, or, in other words, flowing through the heater in such a manner that the air heating devices will not effectively abstract heat from said gases. In the preferred form of my invention, as herein illustrated, the heater comprises a sheet metal casing 1 constructed to form a tortuous air passageway comprising a plurality of passes through which the air circulates in a zig-zag path, and tubular elements combined with said casing in such a manner that they form a substantially straight passageway through which gases flow without reversals, the air which flows through said casing and over the exterior of said elements becoming heated to a high temperature by the heat which said elements abstract from the gases which escape from the boiler. The means that is used to prevent the gases from circulating in lanes, out of direct contact with the air heating elements, consists of one or more mixing chambers arranged intermediate the ends of the gas passageway, so as to effectively break up or mix the gases one or more times while they are circulating through the heater. Preferably, three banks of vertically-disposed, tubular elements 2,

2 and 2 are arranged in superimposedrelation in horizontally-disposed portions of the casing 1, and mixing chambers 3 and 3 are arranged between said banks, as shown in Figure 2, so' as to cause the gases to be broken up and mixed thoroughlya plurality of times in traveling from the inlet end to the discharge end of the substantially straight gas passageway formed by the tubuthe gas passageways. The air t at enters the intake Opening at the upper end-of the casing circulates over the exterior of the tubular elements 2', thence over the exterior of the tubular elements 2, and thereafter over the exterior of the tubular elements 2, finally escaping from the discharge opening at the lower end of the casing. Due to the fact that the gases are thoroughly broken up and mixed in the mixing chambers 3 and 3*, said gases are bound to contact with the tubes 2, 2 and 2 in circulatin through the heater, thereby causing said tu es to become highly heated, and consequently, insuring a high ratio of heat transfer to the air that circulates through the casing of the heater over the exterior of said tubes.

The tubes 2, 2 and 2 of the respective banks are preferably arranged in longitudinal alignment with each other so as to enable soot, dust and the like to be dislodged from same by running a cleaning device longitudinall through said tubes, and the mixing cham ers 3 and 3 are provided with clean-out doors 4 so as to facilitate the removal of soot and dust which collects in said chambers or which falls from the interior of the tubular air heating devices during the operation of cleaning the same. As previously stated, the casing of the heater which constitutes the air passageway is preferably formed from sheet metal, and the tubular elements that constitute the air heating devices and the passageway through which the escaping ases travel are preferabl formed from siort metal tubes whose end portions are expanded or connected in any other suitable way to the sheets that form the top and bottom walls of the casing and the top and bottom walls of the mixing chambers 3 and 3*.

When the boiler is in operation the escaping gases flow through the tubular elements 2, 2 and 2", as indicated by the arrows m in Figure 2, and thus maintain said elements at a high temperature, thereby causing the air that circulates through the casing of the heater, as indicated by the arrows g in Figure 2 to be heated to a high degree. A heater of the construction above described is compact, it is inexpensive to manufacture, and as the mixing chambers'3 and 3 efl'ectively prevent the gases from circulating through the heater in such a way as to not contact directly with the elements that are used to heat the inflowing air, the heater is exceptionally eflicient. Furthermore, such a heater can be cleaned easily to remove deposits of soot, dust and the like from the gas passageways, simply by running a cleaning device longitudinally through said gas passageways. While I have stated that the tubular elements that constitute the gas passageway are disposed vertically and that the casing is provided with horizontally-disposed portions through which air circulates transversely of said tubular elements, it will, of course, be obvious that the gas passageway and air passageway of the heater ,could be constructed and arranged in various other ways without departing from" the spirit of my invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A device for transmitting heat from one gaseous medium to another gaseous medium of a higher temperature, comprising tubular elements arranged so as to form a substantially straight passageway through which the high temperature medium flows without reversals, a mixing chamber intermediate the ends of said passageway, and means for causing the other medium to circulate over the exterior of said tubular elements at an angle'to the path of travel of said high temperature medium.

2. A device for transmittin heat from one gaseous medium. to anot er gaseous medium of a higher temperature, comprisin tubular elements arranged to form a su stantiall straight passageway through which the igh temperature medium flows without reversals, means for mixing said high temperature medium a plurality of times while it is traveling through said passageway, and means for causin the low temperature medium to make a p urality of passes over the exterior of said elements.

3. An air heater of the recuperative type, comprising a plurality of banks of tubes arranged so as to form a substantially straight passageway through which gases circulate, a mixing chamber arranged between said banks and communicating with the interior of said tubes, and means for causin air to circulate over the exterior of the tubes of said banks at an angle to the path of travel of said ases.

4. An air heater of t e recuperative type, comprising an air passageway provided with a plurality of passes through which air circulates in a tortuous path, banks of tubes in said passes arranged so as to form a substantially straight gas passageway and disposed so that the air will flow transversely over the exterior of said tubes, and mixing chambers between said tube banks which communicate with the interior of said tubes.

5. An air heater of the recuperative type,

comprising a casing constructed to form a substantially S-shaped air passageway that comprises a plurality of substantially parallel portions, mixing chambers built into said 5 casing and arranged between the parallel portions of said passageway, and tubular elements arranged transversely of the paralstraight or continuous gas passageway through which gases are adapted to circulate. HENRY F. GAUSS. 

